a) Field of the Invention
The present invention relates to an electronic musical instrument capable of generating musical tones of various tone colors. More particularly, the present invention relates to an electronic musical instrument capable of providing an optimum sound field localization, such as key scale panning, suitable for a selected tone color.
b) Description of the Related Art
Some natural musical instruments have a different sound field for each tone pitch of a sound. For example, a grand piano has a keyboard with 88 keys extended to the right and left sides as viewed from a player, each key having a set of string striking mechanisms which strikes two or three strings in response to the performance of a player. Some instruments drive only one string at the low tone pitch. The position at which a sound is generated in response to the performance of a player, corresponds to the position where the string striking mechanism strikes a string. The string striking mechanisms are also disposed extending to the right and left sides as viewed from a player. Therefore, there are different sound generating positions for high tone pitch side and low tone pitch side. A different sound generating position for each tone pitch is clearly sensed, particularly by a player.
Some of recent electronic musical instruments simulate the sound generating positions of a natural musical instrument by changing the sound generating position in accordance with a tone pitch, as disclosed for example in Japanese Utility Model Laid-open Publication No. 61-49397. For example, a plurality of loudspeakers are installed within an electronic musical instrument to the right and left sides as viewed from a player. The levels of sounds to be generated at the right and left side loudspeakers are changed in accordance with the tone pitch of a depressed key, to make the sound generating position correspond to the tone pitch. This configuration is called a key scale panning or sound field localization.
In a conventional electronic musical instrument capable of executing the key scale panning, a panning data corresponding to the tone pitch of a sound to be generated is read from a table, and a tone signal is divided into right and left tone signals in accordance with the panning data to generate musical tone signals. The table stores panning data beforehand in accordance with which the levels of sounds to be generated at the right and left side loudspeakers are determined in order to obtain the sound field suitable for the tone pitch.
Generally, electronic musical instruments generate sounds by selecting a desired tone color from a plurality of tone colors. The key scale panning is not necessary for some tone colors. Therefore, the key scale panning is not executed for all tone colors, but it is executed only for predetermined tone colors.
In the conventional electronic musical instrument described above, when a tone color which requires the key scale panning is selected, the same key scale panning is executed irrespective of the type of the selected tone color. Therefore, the range of sound field localization becomes too narrow or wide depending upon a selected tone color.